Files
ktransformers/kt-kernel/examples/test_apply_rope.py
2025-10-12 05:13:00 +00:00

53 lines
2.0 KiB
Python

import torch
def rotate_half(x):
"""Rotates half the hidden dims of the input."""
x1 = x[..., : x.shape[-1] // 2]
x2 = x[..., x.shape[-1] // 2 :]
return torch.cat((-x2, x1), dim=-1)
def apply_rotary_pos_emb(q, cos, sin, position_ids=None, unsqueeze_dim=1):
"""Applies Rotary Position Embedding to the query and key tensors.
Args:
q (`torch.Tensor`): The query tensor.
k (`torch.Tensor`): The key tensor.
cos (`torch.Tensor`): The cosine part of the rotary embedding.
sin (`torch.Tensor`): The sine part of the rotary embedding.
position_ids (`torch.Tensor`):
Deprecated and unused.
unsqueeze_dim (`int`, *optional*, defaults to 1):
The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and
sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note
that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and
k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes
cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have
the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2.
Returns:
`tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding.
"""
cos = cos.unsqueeze(unsqueeze_dim)
sin = sin.unsqueeze(unsqueeze_dim)
b, h, s, d = q.shape
q = q.view(b, h, s, d // 2, 2).transpose(4, 3).reshape(b, h, s, d)
q_embed = (q * cos) + (rotate_half(q) * sin)
return q_embed
def my_apply(q,cos,sin):
qa = q[:,:,range(0,64,2)]
qb = q[:,:,range(1,65,2)]
q1 = (qa * cos - qb * sin)
q2 = (qb*cos + qa*sin)
return torch.cat((q1,q2),-1)
num_heads = 128
seq_len = 1024
rope_size = 64
# theta = torch.randn(, dtype=torch.float32)